This invention relates to well drilling and cementing operations.
A universal fluid is a drilling fluid containing cementitious material which, during drilling, forms a settable filter cake upon the walls of the borehole and ensures that bypassed mud after displacement sets up, thus providing lateral support to the casing. After drilling is completed, more cementitious material is added to the universal fluid, along with activator, causing the universal fluid to set to a cement, and bond to the filter cake.
A problem with this system is in maintaining resistance of the universal fluid to setting up and at the same time maintaining good drilling fluid properties after extensive use of the universal fluid.
The present invention provides the answer to this and other problems as will become apparent hereinafter.